Family: Rubiaceae
Cinchona pubescens, commonly known as quinine or red cinchona, is a fast-growing evergreen tree native to the Andes of South America. It is best known as the original source of quinine, a compound historically used to treat malaria and still valued in medicine today. The tree typically reaches 30–50 feet tall, with broad, velvety leaves and clusters of fragrant pink to reddish flowers. Because of its medicinal importance, red cinchona has been widely planted around the world in tropical regions, including Hawaiʻi, primarily for research, cultivation, and ornamental purposes.
Despite its usefulness, Cinchona pubescens poses serious ecological risks in Hawaiʻi. The species readily escapes cultivation, spreads by abundant wind-dispersed seeds, and can form dense stands that outcompete native plants, especially in wet and mesic forests. Its ability to alter forest structure and light availability threatens native understory species and ecosystem processes. In Hawaiʻi, red cinchona is naturalized on Maui and Hawaiʻi Island and is potentially naturalizing on Oʻahu, raising concern about further spread. Due to its invasive behavior elsewhere in the tropics and its documented impacts in Hawaiʻi, this species is considered a significant threat to native forest ecosystems and should be managed carefully to prevent further establishment.
High Risk Traits:
- Highly invasive outside native range – Naturalized and invasive in Galapagos, Hawai‘i, and French Polynesia, displacing native vegetation.
- Broad environmental adaptability – Thrives in tropical/subtropical climates (USDA zones 11-12), tolerates a range of elevations (1000–3000 m) and high rainfall (1400–4000 mm).
- Environmental weed – Forms dense thickets, shades out native plants, and invades both disturbed and intact native forests.
- Rapid growth – Grows 1–2 m per year, matures early, and starts flowering in 2–3 years.
- High reproductive output – Produces prolific wind-dispersed seeds; seeds remain viable for years.
- Tolerant of mutilation – Resprouts from cut stumps and roots, making mechanical control difficult.
- Shade-tolerant at some life stages – Seedlings can establish in dense understory vegetation.
Low Risk Traits:
- Not parasitic, toxic, or allergenic – No evidence of toxicity to humans or animals; not parasitic.
- Not a host for major pests/pathogens – Although fungi are associated, no evidence of being a vector for economically important pathogens.
- Not adapted to fire – Does not tolerate fire; grows poorly on fire-exposed soils.
